Check HTTPS compatibility: Ensure that both the parent SSO application and the child SSO application are properly configured to support HTTPS.
Verify that the SSO URLs are correctly set to use HTTPS.
Check if there are any options to allow embedding via iframes or enable (CORS). Adjusting these settings may help prevent HTTPS redirect issues.
Implement a proxy or reverse proxy server that handles the HTTPS traffic and acts as an intermediary between the parent SSO application and the child SSO application.
This way, the browser sees the proxy as the source of the iframe, and the HTTPS redirect issues can be resolved.
You can verify you URL on this tool RedirectChecker.com to get detail redirection path and its redirection status code.